Chemical feeders can be used to produce various mixtures, such as aqueous solutions of water treating agents that can be used for the disinfection of effluent from sewage treatment plants, for the chlorination of water in swimming pools and hot tubs, and for the delivery of other water soluble chemicals, such as pH control agents, to aqueous streams and water systems. In some instances, a solid treatment chemical is placed within the chemical feeder, where it comes into contact with a liquid, such as water, introduced therein so as to form a treated liquid composition, such as a treated aqueous composition. It is typically desirable that the chemical feeder produce treated liquid compositions that contain a controllable and reproducible level of treatment chemical therein. Variability in the rate at which a solid treatment chemical dissolves in the liquid that is introduced into the chemical feeder can result in an undesirable variation in the concentration of treatment chemical in the treated liquid that is removed from the chemical feeder during operation thereof. In the case of pH control agents, for example, such variability in the concentration of the pH control agent(s) can result in undesirable variability in the pH of the treated liquid. In some instances, pH control agents are used to adjust the pH of a liquid stream containing sanitizing agent(s) for purposes of optimizing the performance of the sanitizing agent(s). If the concentration of pH control agent(s) drops below or above a predetermined operating range, the performance of the sanitizing agent can be undesirably reduced.
In some situations, the solid treatment chemical charged to a chemical feeder is exposed to excess liquid, which results in the solid treatment dissolving too quickly, and/or the formation of a treated liquid having an undesirably high level of treatment chemical. The solid treatment chemical dissolving too quickly can result in the need to frequently charge the chemical feeder with new or replacement solid treatment chemical.
To reduce the frequency of charging a chemical feeder with new or replacement solid treatment chemical, the dimensions of the chemical feeder can be increased, so it can hold a larger amount of solid treatment chemical. Chemical feeders having larger dimensions can undesirably provide a treated liquid output having an undesirably variable amount of dissolved solid chemical therein.
It would be desirable to develop new chemical feeders that can be used to produce treated liquid compositions from solid treatment chemicals. It would be further desirable that such newly developed chemical feeders provide a desirable rate at which the solid treatment chemical dissolves, and a controllable, reliable, and reproducible level of treatment chemical in the treated liquid compositions that are removed from the chemical feeder. It would be further desirable that such newly developed chemical feeders can be scaled up to larger dimensions without compromising desirable performance properties, such as providing a controllable, reliable, and reproducible level of treatment chemical in the treated liquid compositions that are removed from the chemical feeder.